In recent years, a heat transfer system has been developed for preparing a print from an image which has been electronically formed in a color video camera. In one method for preparing such a print, an electronic image is first subjected to color separation with a color filter. Next, the respective color-separated images are converted to electric signals. Subsequently, these signals are modulated to generate electric signals for yellow, magenta and cyan, and then these signals are transmitted to a thermal printer. In order to obtain the print, a dye-providing material of yellow, magenta or cyan is disposed face to face on a dye image-receiving material. Then, both are interposed between a thermal head and a platen roller and are heated from the backside of the dye-providing material with a line type thermal head. The thermal head has many heating elements, which are heated one by one in response to the yellow, magenta and cyan signals. Subsequently, this procedure is repeated for the other two colors. Thus, a color hard copy corresponding to the original image seen on a display can be obtained.
In another method of thermally obtaining a print with the electrical signals mentioned above, the thermal head can be replaced with a laser. In this system, the dye-providing material contains a substance capable of intensely absorbing laser light. The laser light is irradiated on the dye-providing material, and the absorptive substance converts the light energy to thermal energy; the energy is immediately transferred to the neighboring dyes, whereby the dyes are heated to a thermally immigrating temperature in order to transfer the dyes to the image-receiving material. The absorptive substance is present under the dye in a layer and/or is mixed with the dye. A laser beam is modulated with the electric signals corresponding to the shape and color of the original image, and only the dyes in the area necessary to be thermally immigrated in order to reconstruct the colors of the original image are heated for thermal transfer. More detailed explanations of the above process can be found in British Patent 2,083,726 A, in which the absorptive substance disclosed therein for the laser system is carbon.
The problem in using carbon as the absorptive substance lies in the fact that carbon comprises fine particles and that it is liable to flocculate in coating, which deteriorates the quality of the transfer-red image. Further, carbon is transferred to the image-receiving material by adhesion or abrasion, which causes speckles and insufficient color in the color image.